1. Field of the Invention
The present invention relates to a display device, particularly, to a technique that is effective for the application to a display device equipped with a touch panel in which a liquid crystal panel is equipped with a touch panel function.
2. Description of the Related Art
A display device including a device referred to as a touch sensor or a touch panel, which performs a touch operation (a contact pressing operation, hereinafter, simply referred to as a touch) on a display screen using a finger of a user, a pen or the like to input information, has been used for a mobile electronic apparatus such as a PDA and a portable terminal, various home electric appliances, an automated teller machine or the like. As such a touch panel, a resistive membrane type of detecting a resistance valve change of a touched portion, an electrostatic capacity type of detecting a change of the capacity, an optical sensor type of detecting a change of an amount of light or the like have been known.
The touch panel of the electrostatic capacity type is provided with scanning electrodes (Y electrodes) for a drive signal application placed lengthwise and breadthwise in a two dimensional matrix form, and detection electrodes (an X electrodes) for signal detection perpendicular to the scanning electrodes, and the capacity of each electrode is detected in an input processing unit. When a conductor such as a finger comes into contact with the surface of the touch panel, since the capacity of each electrode increases, the input processing unit detects the increase, and calculates the input coordinate on the basis of the signal of the change of the capacity detected by each electrode.